4.2 Network issues and communication
Cambridge IGCSE ICT 0417 · Topic 4: Networks and the effects of using them · Paper 1
Say each word, then read what it means. Every one is in the glossary too.
Read it here, or open the study page below to go one step at a time with things to try.
Data on a network can be intercepted, changed or stolen. Networks also spread malware quickly.
Authentication means proving that a user is who they say they are, before they get access.
Common protections: user IDs and passwords, firewalls, encryption of data being sent, and anti-malware software.
A weak password is short or easy to guess: a name, a birthday, a word from the dictionary, `123456` or `password`.
A strong password is long and mixes upper-case letters, lower-case letters, numbers and symbols. It is not a real word and is not linked to the user.
Each extra character multiplies the number of possible passwords. So length matters most. Type passwords into the checker and watch the time to crack change.
A strong password is still unsafe if it is reused on many sites, written on a sticky note, or never changed after a data breach.
There is something to try for this step in the IGCSE library.
Passwords are the most common method. They are cheap and easy, but can be guessed, forgotten, seen by shoulder surfing or stolen by spyware.
Biometrics use a unique part of a person's body or behaviour: fingerprint, face, iris or retina, voice or handwriting.
| Biometric | Advantage | Disadvantage |
|---|---|---|
| Fingerprint | Quick and cheap; unique to each person | Dirty or cut fingers may not be recognised |
| Face recognition | No contact needed | Lighting, glasses, beards or ageing can cause errors |
| Iris / retina scan | Very accurate and very hard to fake | Expensive; retina scanning is intrusive |
| Voice recognition | Works over the phone; no extra hardware on a phone | Colds and background noise cause errors; can be recorded and replayed |
Biometrics are more secure than passwords because a body feature cannot be forgotten, shared or easily guessed.
A magnetic stripe card holds data such as a staff ID on its stripe. It is swiped to open doors. Cheap, but easy to copy and damaged by magnets.
A smart card has a chip that stores and processes data, often with an RFID antenna. It is harder to copy and can hold more data. Often used with a PIN.
A physical token is a small device that shows a one-time password (OTP). Some need the user's PIN first. Banks use them for online banking.
An electronic token is software, usually an app on a phone, that creates a one-time code or approves a log-in. Codes change every 30 to 60 seconds, so a stolen code is soon useless.
A token's code is a one-time password. Say why it helps: even if it is intercepted, it cannot be used again.
Zero login is a way of authenticating without typing anything. The system recognises the user from biometrics and behaviour, such as how they hold the phone, how they type and where they usually are.
Advantage: very convenient, and nothing to forget.
Disadvantage: the system collects lots of personal data, users may not know they are being tracked, and it is harder to tell how secure it is.
Malware is software designed to harm a computer or steal data, such as viruses, spyware and ransomware.
Anti-malware software (including anti-virus) scans files and emails, compares them with a database of known malware signatures, and watches for suspicious behaviour.
Infected files are quarantined (isolated so they cannot run) or deleted. The software must be updated regularly so it knows about new malware.
On a network, one infected computer can infect all the others, so every device needs up-to-date anti-malware.
Video conferencing uses webcams, microphones, speakers and screens so people in different places can see and hear each other live.
Audio conferencing uses only sound: a phone call with three or more people, or an internet call with no video. Participants often dial a number and type a PIN.
Web conferencing (webinars) runs in a browser or app. As well as video and audio, users can share screens, chat by text, use a whiteboard and vote.
| Advantages (all types) | Disadvantages (all types) |
|---|---|
| No travel, so saves time, money and fuel | Needs a reliable, fast internet connection; lag and dropped calls |
| Meetings can be set up at short notice | Time zones make scheduling hard for international meetings |
| People can join from anywhere, including when ill or abroad | Less personal: body language is harder to read |
| Safer: no travel risks | Equipment costs (webcams, headsets, software licences); security risk if calls are hacked |
Open the study page and go one step at a time.
Step by step, with exam questions and a quiz.
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Topic 17 · Year 9Cybersecurity protects computers and data. Most attacks trick people or exploit weak systems, so defences cover both.
One question at a time. The reason shows after each answer.